hvol man page
hvol — display or change the current HFS volume
With no arguments, hvol displays the name and path to the "current" HFS volume as well as the names and paths of all previously mounted ("known") volumes.
With an argument, hvol changes the current volume to be the one specified. Either the name of the volume or the path to its UNIX source can be specified. The volume must have been previously mounted using hmount.
A separate "current working directory" is maintained for each mounted volume. This information is kept in a file named .hcwd in the user's home directory.
hfsutils(1), hmount(1), humount(1)
Robert Leslie <firstname.lastname@example.org>